One of the biggest challenges that a prosthetic implant has to overcome is the reliable packaging of integrated circuit (IC) chips with bio-devices to withstand corrosive body fluids. This is especially true for complex neural implants and retinal implants because hundreds of or thousands of electrodes may be needed to be connected to the necessary IC chips (see, K. D. Wise et al., International Conference of the Engineering in Medicine and Biology Society on Neural Engineering 2007, pp. 398-401). In comparison, a pacemaker has only one stimulating channel and a cochlear implant requires only 5 to 6 stimulating electrodes to be able to regain hearing capabilities of an impaired patient (see, K. Najafi et al., IEEE Conference on Nano/Micro Enginnered and Molecular Systems, 2004, pp. 76-97). In addition, in order to avoid possible infection and medical complications, it is desirable to have prosthetic devices completely inside a subject's body. This means that technologies for integration, connection and packaging of IC chips for high-lead-count implant devices are of high demand. As shown previously, aligned electrical connection can be done between parylene-C interfaces and high density multi-channel chips by a conductive epoxy squeegee technique (see, Jay H. C. Chang, Ray Huang, and Y. C. Tai, Proc. TRANSDUCERS 2011, pp. 378-381), where a PDMS mold was used to house the IC chips and serve as the safety squeegee buffer zone. However, it is too big to be implanted inside a human eyeball (<1˜2 cm3) (see, M. Humayun et al., Vision Research, 43 (2003), pp. 2573-2581). In addition, since the adhesion only relied on conductive epoxy contacting less than 2% of the total connection area, delamination could easily happen when even a small force was applied to the assembled devices. This would be especially serious during surgery. Since the next generation intraocular retinal prosthetics require the whole device, including coils, electrodes, stimulation chip and other ASICs to be fitted inside a human eyeball, the device must be further designed in terms of both size and surgical complexity.
Parylene-C has become a popular material for BioMEMS implant applications due to its superior properties (see, J. H. Chang et al, Proc. TRANSDUCERS 2011, pp. 390-393; J. H. Chang et al, Proc. NEMS 2011, pp. 1067-1070). It has also served as an intermediate layer for silicon wafer bonding (see, H. Noh et al, J. Micromech. Microeng. 14(2004), 625; H. Kim et al., J. Microelectromech. Syst. 14(2005), 1347-1355). However, the bonding between parylene-C and silicon is still problematic.
There are various processes for packaging integrated circuit (IC) dice. Some packaging techniques contemplate the creation of electronic modules that incorporate multiple electronic devices (e.g. integrated circuits, passive components such as inductors, capacitor, or resisters) into a single package. Despite the advances of the prior art, and although implantable devices have been developed with micro-electrical-mechanical system (MEMS) technology, there is a need for better packaging technology, especially for high-lead-count retinal and neural implants. The present invention provides these and other needs.